Carbonaceous feed material such as coal, wood chips and other biomass, and the like, have been used to produce synthesis gas which is carbon monoxide and hydrogen. The syn gas reaction is a redox reaction in which steam is combined with carbon at elevated temperatures to produce carbon monoxide and hydrogen. The reaction generally occurs at greater than 1000° F. Generally, the carbonaceous starting material includes oxygen which at elevated temperatures, i.e., greater than 450° F., will react with the carbon and pyrolysis will occur. This is an exothermic reaction. Most syn gas production has utilized the heat generated in this portion of the reaction to fuel the subsequent gasification.
Unfortunately, the pyrolysis reaction has several undesired results. Primarily it produces carbon dioxide which must be removed. Further, it produces large amounts of ash and further creates slag. Basically, it raises the temperature of the feed material to above the melting point of the ash, forming slag. Slag is unusable and must be disposed.